IDENTIFICATION AND QUANTIFICATION OF POTENT ODORANTS FORMED BY TOASTING OF WHEAT BREAD

Slices of wheat bread were toasted until a distinct intensity of brown colour was attained. Potent odorants formed were evaluated by aroma e xtract dilution analysis and gas chromatography/olfactometry of headsp ace samples. Compounds showing high dilution factors were quantified a nd their aroma activity values (OAV, ratio of concentration to odour t hreshold) were calculated on the basis of their odour thresholds in st arch. The roasty smelling 2-acetyl-1-pyrroline (I) showed the highest OAV followed by (E)-2-nonenal (II), 3-methylbutyric acid (III), 4-hydr oxy-2,5-dimethyl-3 (2H)-furanone (IV), methional (V) and 2,3-butanedio ne. Formation of nine odorants (I to V among others) was measured in r elation to the intensity of the brown colour. It was found that, at th e beginning of toasting, (I) increased more rapidly in the bread slice s than (IV) which was mainly produced at medium browning. (C) 1996 Aca demic Press Limited